Cranial Spreader Pivot Axis In-Plane Arm Design

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Solution Overview

Problem

Conventional spreaders for cranial surgery lack sufficient strength and variability in the connection between clamping arms and articulated parts, limiting their flexibility and safety during use.

Innovation Solution

The spreader design features pivotable tensioning arms with a pivot axis connected via an in-plane arm, allowing for larger bending radii and improved positioning, along with toothed rims for stable angular alignment, and a holder for brain spatulas, enhancing flexibility and safety. Additionally, the use of shape-memory materials for the spatula and a ratchet lock for secure positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the pivot axis is connected directly to the joint part, then the structure is compact and simple, but the clamping arm cannot reach the same areas with sufficient flexibility and the clamping process is difficult

Engineering Contradiction:
Improveclamping processVSAvoidstructure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention introduces an in-plane arm that extends the pivot axis connection outwardly from the joint part, effectively adding a spatial dimension to the connection. This allows the tensioning arm to be positioned at a greater distance from the axis of rotation, enabling the clamping arm to reach the same areas with larger bending radii and less bending, thereby facilitating the clamping process while maintaining structural integrity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the tensioning arm is positioned close to the joint part, then the structure is compact, but the positioning and contraction of the tensioning arm is obstructed

Engineering Contradiction:
Improvepositioning and contraction of tensioning armVSAvoidstructure
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

By extending the pivot axis connection outwardly via the in-plane arm, the invention creates additional spatial room for the tensioning arm to move and position itself. This dimensional extension allows the tensioning arm to be positioned and contracted unobstructed, as it has more space to operate without interfering with the joint part or other components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the connection between clamping arm and joint part is fixed and rigid, then the structure is stable, but the spreader lacks flexibility for different applications

Engineering Contradiction:
Improveflexibility for different applicationsVSAvoidconnection strength
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention employs a pivotable connection between the clamping arm and the joint part via the in-plane arm and pivot axis, allowing the connection to dynamically adjust its position and orientation. This dynamic capability enables the spreader to adapt to different applications and surgical requirements while maintaining stable fixing when needed, as the pivotable connection can be locked or positioned in specific configurations.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design facilitates more flexible and stable clamping, allowing for unobstructed positioning and contraction of the tensioning arm, reducing the risk of injury and improving the overall usability and service life of the spreader.

Implementation Method 1

the brain spatula is made of a shape-memory material, such as nitinol, which can be shaped as desired for the surgical purpose, especially at room temperature, and regains its original shape during processing under the thermal influence of hot rinsing water

Methodology Applied
Scientific EffectShape-memory effect: Shape Memory Alloy

Data Source

PatentEP2889006B1Spreader, in particular for cranial surgery
Publication Date: 2018.01.31 FEHLING INSTR GMBH
  • EP2889006B1 patent drawingFigure 1a~1d
  • EP2889006B1 patent drawingFigure 2a~2c
  • EP2889006B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a spreader (10), particularly for cranial surgery, with two joint parts (12a, 12b) pivotable relative to each other about an axis of rotation (dA), wherein each joint part (12a, 12b) has a handle part (14a, 14b) at its proximal end and a spreader element (16a, 16b) at its distal end, wherein the joint parts (12a, 12b) each span a plane with a section (18a, 18b), and wherein a tensioning arm (20) is arranged on at least one of the joint parts (12a, 12b), wherein the tensioning arm (20) has several tensioning elements (22) which are threaded onto a pull cable and which interlock section by section and are tiltable and/or rotatable relative to each other, wherein the tensioning arm (20) is pivotably arranged about a pivot axis (S1A) and the pivot axis (S1A) is connected via a The plane-arranged arm (19a, 19b) is connected to the joint part (12a, 12b), wherein the arm (19a, 19b) is directed outwards from the joint part (12a, 12b),so that the pivot axis (S1A) is spaced apart in the plane from the joint part (12a, 12b).